Components of a Suspension Bridge and its Advantages

A common suspension bridge is essentially isolated into two fundamental parts, “superstructure” and “substructure.” Following are the segments of a suspension bridge,

Deck
Main Suspension Cables
Hangers
Pylons(tower)
Pylon Foundation
Anchorages

Deck: Deck is suspended from the principle suspension cables by utilizing vertical or inclined hangers (suspenders). This part of the bridge is comprised of numerous steel trusses and it is the span of the bridge. The main function of this is to convey the load going ahead. Traffic loading is the most significant load which is carried by the deck. Since the deck is suspended from the cables, the self-weight must below. To transfer the loads from deck to hanger, a stiffening girder should be provided in the deck.

Components of Suspension Bridge

Main Suspension Cables: The primary function of suspension cables is to support the deck system which conveys the traffic loadings. And by direct tension force, these cables transfer the traffic loading to the pylons and anchorages. High strength steel wires or eyebar chains are utilized as suspension cables. The high tensile strength wire is acquired by cold drawing the wire. For corrosion protection, the wire is galvanized after the final drawing.

Various kinds of cables are as per the following,

a)Spiral Bridge Strands b) Locked Coil Strands c) Parallel Wire Cable

Types of Suspension Cables

Hangers: Hangers are used to associate the stiffening girder and deck of the bridge to the principle cables firmly. Hangers likewise arranged like the suspension cables. They are chiefly associated with vertical and inclined structures. In general vertical hangers with equal intervals are used across the span of the bridge.

Types of Hangers

Pylons: The principle function of a pylon is to support the main cables. The terminals of the main cable are joined to the pylon at an appropriate height to provide cable sag. Pylon supports the stiffening girder just as a side span. The pylon is provided with a flexible fixed base and secured with cable saddles on the highest point of the pylon. Since this kind of arrangement is made, any development in the cable saddle will result in the longitudinal bending of pylon legs due to varying load.

Shapes of Pylon

Pylon Foundation: Foundation is the part of the Suspension Bridge on which the Pylon is resting. This foundation can either be on the ground or even below water. Construction of below water foundations requires more effort and time.

Anchorages: The main role of anchorage is to sustain the ends of the main cable. By exchanging the force from the main cable to the ground, anchorages avoid the movements in the main cable. The ground on which anchorage is to be positioned should be good and should have enough availability of sound rock, otherwise, the design of anchorages become tough since it has to resist a large force. In a suspension bridge, the cables are either self-anchored or externally anchored.

LOAD TRANSMISSION

Suspension bridge works by tension and compression. The weight of the traffic and deck is supported by a tension force in the main cables through hangers (suspenders). Subsequently, the main cables are held up by the towers, the entire bridge weight is carried down through the towers by compression force and then transmitted to the underlying tower foundations. In a suspension bridge the road deck is supported by the stiffening girder, which spreads out the traffic weight, henceforth it avoids the excessive sag under exceptional loads. And also in a suspension bridge, if a heavy load moves over the bridge, it will not only sag downwards at the point of load and also move longitudinally towards the nearby tower.

LOAD TRANSMISSION SEQUENCE IN SUSPENSION BRIDGE

ADVANTAGES OF SUSPENSION BRIDGE

A suspension bridge is a unique style of bridge among all types, which accomplishes the following advantages,

Long span: Longer span of a bridge can be achieved by the suspension bridge type that can span about 2000-7000 feet. No other kind of bridge can achieve more than this. So it is often the design being preferred by specialists to interface the distant locations.

Inexpensive to construct: Construction of a Suspension bridge requires fewer materials, for example, anchorage, cables, and roadway even at longer spans leading to the decreased construction cost. And furthermore, even with just timber and rope, the construction of a useful bridge is always a possibility.

Easy maintenance: Maintenance of suspension bridge to keep it strong and long-lasting, is easy as it does not need a lot of materials. Communities should not need many expenses just to keep the bridge functional.

Earthquake resistance: Suspension bridge might be superior to withstand seismic forces than the stiffer and heavier kind of bridges.

Good aesthetic view: While discussing the design of bridges, a vital issue is to consider its aesthetics. Unlike other types of bridges, the construction of suspension bridges can be aesthetically pleasing. Its curved shape, hanging cables and linear features add to the beauty of the suspension bridge which makes it attractive to the people.

Flexibility: Suspension bridges are very flexible as they can be modified easily to add additional lanes and to accommodate wider vehicles.

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